SawStop GIF

SawStop GIF.

This is the type of table saw that is marketed as stopping as soon as you accidentally cut your finger. I've never used one, but I know that they work by monitoring the difference in electrical conductivity between wood and human flesh. A small amount of voltage is applied to the blade, and the current is continuously monitored. Once a change in this current is detected, a braking block is forced into the saw blade.

After various licensing battles involving tool companies and the SawStop inventor, an amateur woodworker and physicist named Steve Gass, this same technology is now finding its way into other mainstream saw brands.

https://diqn32j8nouaz.cloudfront.net/sawstop.gif
https://diqn32j8nouaz.cloudfront.net/sawstop.gif

My understanding is that, when activated, the device destroys itself, the saw blade, and perhaps other bits of the saw in the process of stopping the saw. The cost and time to make the saw operational again is, of course, of no account if it saved someone's digits but might be problematic if the wood is a bit wet or salty.

Secondly, I'm not about to trust my body parts to a bit of electronics that may or may not be working properly when I need it to do its thing. Even on some of the man-rated space stuff I worked on where the consequence of failure was death was it possible to achieve 100% reliability. Kickbacks can inflict serious injury too. The next step will be some electronic gizmo to sense that. Soon the saw blade will be festooned with sensors and devices that will need to have all possible interactions accounted for in a (human coded) program in the onboard computer. Yeah, good luck with having all that fail safe.

Finally, I'm strongly opposed to the current infatuation with having everything done for you so, presumably, you can update your Facebook status while driving, welding, sawing, crossing the street, etc.. If you don't learn to pay attention to what you're doing and practice self-protection it's inevitable that you'll encounter a situation where they haven't yet installed the gadget to save your derrière and you'll join the legion of Darwin Award winners (assuming you have no offspring).

Yeah, still qualifies as "gimmicky". You're spot on about wet wood; the recommendation is to deactivate the brake system for green timber. The concept of using the different conductivity between metal and flesh for increasing safety may have other uses.

The backstory on Gass's scuffle against existing tool manufacturers is interesting. He has a UCSD doctorate in physics, plus a law degree. It sounds like he was in licensing negotiations with Ryobi, but maybe they played the negotiations as a "fishing expedition" - dragging out talks as they gained information and time, while conveniently failing to correct a typographical error in the contracts.

Then the politicians got whiff of the "safety" angle, and started to push on legislation to mandate SawStop-like additions on new saws. No joke, here are some of the bills:

Illinois HB0450 - "Requires a saw manufacturer to retool its production line to install the SawStop safety device on all electrical saws."

California AB 2218 - "This bill would prohibit a seller, on or after January 1, 2016, from selling a new table saw in this state unless that table saw is equipped with injury mitigation technology, as defined."

Note how AB 2218 tries to piggyback the rationale for SawStop requirements on other much more reasonable safety laws - those regulating the manufacture of products intended for children: "bunk beds, infant cribs, and toys".

You can turn it off? It's not hot-wired into the saw power? If it's turned off when you start the saw does it sound a siren to warn you that you're not protected from your own inattention?

See where I'm going with this? The more bells and whistles required to make it practical just provide more opportunities for it not to be working when you push your hand through the blade because you were watching football on the shop TV while sawing fence rails. (Don't laugh, a well-educated engineer who lives a few doors down did just that.)

I can completely understand a lawyer wanting to get his product made mandatory. I can hear the whining now...but, it's for the children!

It doesn't surprise me that there is more a monetary than true safety angle to it. What are you going to do when it gets a false positive and destroys itself? Or worse yet it bites your finger just enough get it tangled but it's now the device has destroyed itself and won't turn to let your finger go?

I'm with Marv, the best safety device is between your ears. The four carpenter/cabinet makers I know have all had fingers/thumbs cut off and all said it was their fault, not the saw. If I'm not in hyper vigilant mode on any machine I back off. Soon as I'm too comfortable and not wary is when I get hurt.

Engage brain before hitting the switch, period.

It is disheartening though to see another law that seems to be doing more damage than good. Over in Hobby Machinist there's a thread going on that started with a guy ordering I think a rotary table from Grizzly and they cancelled the order because of the change to a law that says you can't sell brass with lead in here. Needless to say that's caused quite a row and a round of CA bashing.

Oh Boy, Howdy! "It is impossible to make anything foolproof, because fools are so ingenious." anonymous, (theoretically Murphy's 3rd law). Lord knows I spent half of my engineering career developing products with that on the forefront...and only got close.

Personally I prefer common sense and mechanically oriented safety systems. How about a foot switch with a quality braking system engaged when switch is turned off. The idea of a saw that self destructs based on "Relative" conductivity scares me more than the saw. First off I know my skin resistance is less than most people for some reason and second for the obvious stated above and then to disengage it because I'm cutting green wood...I'll be sure and stick with Old Saws, Thank You anyway!

I know Absolutely if I use a push stick and stay a bit offset from the diametral axis and keep all my other body parts way the heck away from a metal blade spinning at ~3k rpm that my body parts should be fine...but no guarantees. Kick back or other distractions are just not allowed in my mind. Still the possibilities exist for a blade to explode or being hit by a comet... Maybe we could buy Insurance for that¿ Support for legalized gambling is a whole other babbling hole...rabbits are banned legislatively.

To be legislated into having to buy (pay the additional legislative cost, tax and hardware/software) once again scares me more than the saw or going into space to wrestle a comet for that matter.

I am with Marv, C-Bag, PJs and Jon on why this is a bad idea. The best way to be safe when using your table saw is to combine common sense with your eyes, ears and nose. Just listening to your saw can avoid at lot of problems and if it seems like your are taking a chance, just don't do it, because there are too many other ways to do the work safely.

I guess I don't have to ask what the consensus on self-driving cars is, do I?

I take it you're not a fan? I know there are a bunch of people locally old and young, who should not be allowed to drive. I guess it just depends on how "smart" the system is. Personally I don't think self driving cars are as stupid as the saw stop. Our new Volt has several safety systems like one that gently steers you back into the lane and warns you when there is something in front of you and you can't stop in time along with proximity warnings , blind spot warning and a rear camera. As long as they continue to function like they do right now I find them useful. But if they turn into bugs in the machine that can't be fixed I'm going to change my opinion, quick.

But I'm often wrong.....

The biggest thing to me about the autonomous vehicles are them being hacked. Even the new cars with all the electronic systems are vulnerable to this. If you think about just the lo-jack systems and consider you were driving on the 405 in LA, in rush hour at 70+ bumper to bumper, fiddling with a c-phone or the MP3 music list and someone remotely pulled the plug on a few vehicles. It wouldn't matter how many safety systems you have "On-Board"...it wouldn't be pretty.

Right now it seems at least for the last decade (actually since McAfee sat in a dark room for 3 years way back when) or so, we are in horn locked battle between the black hats and white hats. Now we have governments and large corps. perpetrating the same processes of control of information and cyber space. I call it the dichotomy of distraction which leads to complacency in responsible thinking and action...all the while drooling over the next iToy.

Developing an autonomous vehicle or a safety saw stop is not inherently a negative in my book. I like the next shining thing that lights my candle...the issue is always how its used, the trickle down from it and disallowing misuse as best we can. Perhaps we might spend some critical thinking time examining the next can of worms before we open the can and legislate it.

You of course are totally right PJs. I for the life of me can't figure out why that wasn't my main concern, brain hack? Guess I forgot I drank the Koolaide :(

I guess I should be glad that you have to take the Volt in to the dealer for software upgrades as that means it's software is not accessible through the satellite link like Tesla. Not thinking about hacking I thought it was kinda cool that Tesla can do upgrades through the satellite link while you sleep. But then I think back to my time in the automotive trenches and shiver. I don't buy anything first gen. Usually, unwittingly the Volt is a Gen II. And that's because I was there when they rolled out the C3/C4 GM computer carburators in the early 80's and bad glitches and poor performance became the nature of the beast excuse by the dealer. And a good portion of my clientele I had to tell them they had to go to the dealer when there was a problem with the black box. It was during that time I decided to quit working on cars and go to packing machinery. Less black boxes and less fixing and more making new along with helping design and manufacture.

I guess I should mention we just went in for 4 software update/recalls and the one that stuck out was a possible software glitch of when the battery runs out there is message "engine not found"..........scary. Knock on wood we've not had any such problem but it is scary how complicated cars have gotten and it's a major reason why we decided for the first time ever to lease instead of buy. One thing I have noticed is there is an option to pick electronic dash configurations. This was reset with the update and now for whatever reason I cannot "select" the enhanced version we usually use. I can page through, but for some reason the select button doesn't select it permanently. Guess I need some more Koolaide.

You pointed out some good things about the various update schemes C-Bag. I'm not sure which is better but they are all based on code jockey work and vulnerable throughout the system. Look what VW/BMW was busted with recently...firmware saying it was a clean machine, worldwide.

Back when rocks were forming I went to C3 school in Freemont...cool stuff I thought and it has all gotten better and much more complex now tying many engine and other subsystems together (brakes, suspension, etc.) mostly in the name of efficiency. However when I was there I got to see several pallet racks in a room that had 50+mpg experimental carbs (mechanical in nature) sitting on the shelves gathering dust...It just never set well with me when I could get 30mpg out of 3 duces on a big block GTO or Mopar.

Now days we have the Racer X kids hacking/modding firmware for street rods, drift cars and such, let alone the big boy racers with telemetry and dynamic feedback systems. All cool stuff but susceptible to human frailty.

When you start tying the fuel system into Variable Valve Timing, idling cylinders one at a time, and electronic advance/retard timing based on load conditions, engine/fluid/exhaust temp with multiple O2/Nox sensors and the almighty GPS with a single black box firmware and microprocessor, even with some redundancy starting to show up, it's all relying on the frailty of still practicing humans, some with natures that shouldn't be appealed to. The more complex the system the more likely a breakdown, maybe even catastrophic, minimally chaotic and expensive, most probably by human frailty.

When I think of the space program and some the stuff Marv got to work on, I see fairly simple well thought out systems with redundancy to safeguard a few people and gather some data. Probably the biggest accomplishment of the 20th century and that was 50 years ago...definitely the Right Stuff and monumental in right thinking, imho. Unfortunately it was underpinned by the presumption of the "Space Race" to dominance and mutually assured destruction. Perhaps if we can see betterment in human kind(ness) and the ecosystem we live in as a way of becoming, instead of "Mo This or That", and mine is bigger than yours we may not meet catastrophe head first.

With the exception of the "gently steering you back in your lane" feature most of what you describe are more in the nature of warning or viewing enhancement features.

I have no problem at all with viewing/warning features, in fact, I would love to have a side-view and rear-view camera like my daughter's new Honda has.

But, I draw the line at anything that attempts to autonomously operate the car for you. If you can't stay in your lane, you have no damn business driving an automobile. (I rate about half the drivers out there in that category.)

There is simply no way anyone can design fail-soft software that is ready to cope correctly with the infinite number of situations which face drivers on a regular basis. If you're too lazy to actually drive your car, stay home or take a bus/taxi/train/subway...whatever.

If you want to see more on this hot topic, including some really laughable pie-in-the-sky nonsense by the Silicon Valley nutjobs, there's a long thread over at HSM...

OT: Autonomous car progress.

My suggestion is that, if you want to discuss this further, do it there. As far as I'm concerned this ranks up there with politics and religion as subjects unfit for discussion in any hobby forum, most certainly this one.

Hey, whatever, I didn't bring it up, you did. And you seem to be the only one who's getting hot about it. Consider it dead, pardon me for replying.

Quote:

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Originally Posted by C-Bag

Hey, whatever, I didn't bring it up, you did. And you seem to be the only one who's getting hot about it. Consider it dead, pardon me for replying.

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My apologies, C-bag. That remark wasn't directed at you. And, you're right, I brought it up.

My concern is that a subject like this can get heated and I get enough of that on other fora. I'd like to avoid it here. I regard this place as an island of calm in a sea of discord.

I won't discuss it again.

Apology accepted Marv.

I also appreciate the calm and respectful vibe here and don't mean to ruffle any feathers.

Nor shall I.

Sorry fellas. I was between this starting and concluding, so my jab is going to irritate a portion. So, edited in some novelty to lessen the blow.

Quote:

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Originally Posted by C-Bag

It doesn't surprise me that there is more a monetary than true safety angle to it...guy ordering I think a rotary table from Grizzly and they cancelled the order because of the change to a law that says you can't sell brass with lead in here. Needless to say that's caused quite a row and a round of CA bashing.

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Have instances occurred where customers are ingesting rotary table components? Don't get me started on lawyers.
Well, as an exCA myself, few get more enjoyment than a former loyalist. Moving here, was asked many times...BUT WHY? Response; going to open a suspender store. A percentage found it plausible.
Personally hate the drive to make things physically 'safe'. Electrical safety and such are one thing. The trend in autos; pedestrian detection; lane departure, auto braking, crash avoidance? What are drivers doing more important than piloting a vehicle, besides maxing out their cell data plan, finishing cosmetics...? I can't wait for the first manufacturer liability suit pursued by defense attorney based on one of those being ineffective.
PJs statement tallies it up. "It is impossible to make anything foolproof, because fools are so ingenious."
Yup, they've got all day too.

I'm not sure that I agree with you blokes. While I hate the idea that my car might one day be uneconomic to repair because the inbuilt intelligence has gone kaput, with the rest of it in good working order, but no new computer system available, the idea that the car of some moron ploughing into me because they were distracted by the show on the DVD player, or were too busy applying makeup, or catching up on twitter etc, when the same moron might have been in a car with adaptive cruise control, or collision avoidance radar is not real flash either. Most morons need all the driving help available, as already stated, they can be so ingenious, and there are lots of them on the roads and highways. The accident statistics are not pretty reading, here in Australia, many more killed on the roads than by murders or unlawful killings, not sure of U.S.figures, but intelligent systems are worth thinking about in my view.

Bandsaw "BladeStop":

https://www.youtube.com/watch?v=NiRegdech_E

What's ironic here is the use of gloves, which of course are generally counterindicated when sawing. In this case, the saw blade stops when it touches the glove.

Patent: Patent EP1909588A1 - Electric saw with operator protection system - Google Patents

The patent talks about detecting a current between the saw blade and the operator. Presumably the gloves are waterproof (else why wear them) so I'm guessing that operation depends on the gloves being wet (and salty) enough on the surface to conduct. If the operator has just donned new gloves he best be careful.

Actually, the real safety action to be taken here is to demand a little less of the operators so they can slow down a bit and not propel their extremities rapidly toward the blade.

Agreed, plus conductive boots. From the patent:

https://diqn32j8nouaz.cloudfront.net...nt_details.jpg

If the operator slowed down, he'd never achieve internet GIF fame! I believe this is done without any automatic blade stopping tech:

https://diqn32j8nouaz.cloudfront.net...at_bandsaw.gif

I like this invention and it is better than nothing, the blade clamp mechanism is the best part of it, but I think that it has very little to do with the glove conductivity. I believe that the blade must start cutting human meat before it activates, otherwise it would activate with a circuit through the animal meat if held with the fingers too close to the blade. The gloves don't seem to have wires attached so are probably insulators, insulating the electrified operator from a possible current path through the carcass. The advantage of this is that it would still work if the operator slipped and presented his shoulder, arm or face to the blade. It did make a shallow cut in the dummy finger/sausage in the glove and I don't think that that is good enough. The faster the operator, the deeper the cut will be. It should never be acceptable for a safety device to just hurt you a little bit. The legal speak in the patent is unbelievable so I may have missed something here. If I was re-designing this I would use optical sensors that sensed the glove, perhaps by colour, when it was at least 6" in front of the blade, and with a good safety margin on the sides. A complete optical no go area, colour sensitive corridor, could be formed anywhere in front of the blade. Then 15ms would be more than enough time to clamp the blade without damaging the operator. Perhaps blue clothing could also be worn to protect arms and shoulders from an accidental fall into the blade.

I am going to have to agree with what others have been saying all along allow the operation to be slowed to a still respectable but much safer pace.
I've tried to never place my hands any where near things sharp or fast enough to remove digits. I prefer to use push blocks or holding devices instead of fingers near rotating blades or bands
There is a very old saying haste makes waste
Maybe situations like the high speed meat cutting operations would be a good place to create a fully automated robotic system.
I once watched the goings on in a fish processing factory the workers men and women wielded huge knives as sharp as any surgical scalpel with blindingly blurring speeds sometimes only a couple of millimeters away from the fingers on their other hand slicing up ice cold fish into filets Sometimes they wold slice off s couple layers of skin and not even know it until they started to bleed. The tips of many workers fingers were blunted and squared off from previous encounters with a blade and yes some were missing a lot more than just their finger tips.

Maybe I'm wrong, but it looks like the glove of the demo does not contain a real finger, but more probably a sausage ...
It reminds me of a similar system for the table saw
https://youtu.be/eiYoBbEZwlk

Yes in the video with the band saw it was a sausage in the glove they said as much.
Having technologies to stop the blades is a good thing not getting yourself in harms way is even better not having to move at such a fast pace that a minor error in judgement or micro momentary lack of concentration which leads to disastrous injuries is even better
Hobbyist should never be in such a hurry to complete a project that can lead to injuries. plus should never allow distractions in their work places such as children spouses and friends to be talking or running around them while they are doing potentially dangerous tasks .or making critical cuts or measurements.

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